TW554640B - Sputtered cathode having a heavy alkaline metal halide in an organic light-emitting device structure - Google Patents

Abstract

An OLED device, including a substrate, an anode formed of a conductive material over the substrate, an emissive layer having an electroluminescent material provided over the anode, a buffer layer provided over the emissive layer and containing a halide of a heavy alkaline metal, and a sputtered layer of a metal or metal alloy selected to function with the buffer layer to inject electrons.

Description

554640 A7 B7 V. Description of the invention (i) The present invention relates to organic light emitting diode devices and methods for manufacturing the devices, which uses an inorganic buffer layer and a base metal or metal alloy sprayed on the inorganic buffer layer. Floor. Organic electroluminescence (OEL) devices, or known organic light emitting diodes (OLEDs), are useful in flat display applications. This light-emitting device is attractive because it can be designed to produce red, green, and blue with high light-emitting efficiency, can be operated with a low drive potential of several volts, and can be viewed from an oblique angle. These unique properties are derived from a basic OLED structure that contains multiple layers of a thin film of small organic material sandwiched between an anode and a cathode. This structure is generally disclosed in US_A-4,769,292 & US-A-4,885,21 1 transferred to Tang and his companions. The general electroluminescence (EL) dielectric system includes a binary structure of a hole transport layer (HTL) and an electron transport layer (ETL). The thickness of each layer is generally tens of nanometers (nm). The anode material is usually an optically transparent indium tin oxide (ITO) film on glass, which also serves as the substrate of the OLED. The cathode is typically a reflective film. The choice of electrode material is based on a work function. Because ITO has a high work function, it is most often used as an anode. Because Mg: Ag alloys have a lower work function, they are generally used as electron injection contacts. Li-containing alloys such as Ai: Li and LiF / A1 contacts can also provide effective electron injection. This device emits visible light in response to the potential difference applied to the EL medium. When a potential difference is applied to the electrodes, the injected holes of the carrier-anode and the electrons of the cathode are moved toward each other through the EL medium and partially recombined to emit light. In the manufacture of OLEDs, a vapor deposition method is used. Using this method, the organic layer is deposited on the IT0 glass substrate in a thin film in a vacuum chamber, and the paper size is applicable to the national standard (CNS) Α4 specification (21G > < 297 public love) · ---

Ij «i 554640 A7

2 Deposit the cathode layer. Among the methods of depositing a cathode, it has been found that a vacuum deposition method using resistance heating or electron beam heating is most suitable because it does not cause damage to the organic layer. However, it is highly desirable to avoid these methods of manufacturing the cathode. This is because these processes are inefficient. To achieve low-cost manufacturing, a proven high-throughput process unique to LED manufacturing must be adopted and developed. Splashing has been used as a method of choice for thin film deposition in many industries. Uniform, in- and adhesive coating, short cycle time, low coating room maintenance costs and effective use of materials are among the few spraying benefits. Sputtering is not often used in the manufacture of OLED cathodes because the organic layers may suffer damage and degrade device performance. Sputter deposition occurs in a high-volume and complex environment, where the environment includes high-energy neutral, electron, positive and negative ions, and self-excited light, which can degrade an organic layer with a cathode deposited thereon.

Liao and his companions (Appl. Phys. Lett. 75, 1619 [1999]) used X-ray and ultraviolet photoelectron spectroscopy to study the damage caused by irradiating Alq surface with 100 eV Ar +. The electron density curve of the core layer revealed that the N-A1 and C-0-A1 bonds in some Aiq molecules were broken. The valence band structure has also changed greatly, which means the formation of a metal-like conductive layer. It suggests that when electrons are injected from the cathode into the Aiq layer, this will cause non-radiative quenching in the OLED and will also cause short circuits. During the sputtering deposition of the cathode, the Alq surface was subjected to high doses of Ar + at hundreds of volts. As revealed by Hung and his companions (j. Appl. Phys. 86, 4607 [1999]), only a dose of 9x1014 / cm2 can be used to change the valence band structure. Therefore, the cathode is sputtered on the surface of Alq in Ar atmosphere. Pre -________ R-This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) 554640 A7 ___B7 V. Description of the invention (3) Expected to reduce the performance of the device. Splash damage can be controlled to a certain degree by proper selection of deposition parameters. In European patent applications EP 0 876 086 A2, EP 0 880 305 A1 and EP 0 880 307 A2, Nakaya of TDK Corporation and their companions have disclosed a method for depositing a cathode using a sputtering technique. After the organic layer was deposited, the vacuum was maintained, the device was transferred from evaporation to the spray chamber and the cathode layer was directly deposited on the electron transport layer in the chamber. The cathode is an A1 alloy containing 0.1 to 20 a% Li, wherein the A1 alloy further contains at least one of cu, Mg, and Zr, and has a protective layer in some examples. Therefore, the produced OLED device without a buffer layer is claimed to have excellent adhesion at the organic layer / cathode interface, low driving voltage, high efficiency, and a slow black dot development rate. Gröthe and his companions also disclosed in a patent application DE 198 07 370 C1 a sputtering cathode of an A1: Li alloy, which has a relatively high Li content and has one or more alternatives selected from Mn, Pb, Pd, Elements of Si, Sn, Zn, Zr, Cu and SiC. In all of these examples, no buffer layer is used, but electroluminescence can be generated at lower voltages. Splash damage can be controlled by the use of low deposition rates. It is expected that damage to the organic layer can be easily reduced by lowering the spray power. However, at low power, the deposition rate may be unachievably low, and the sputter advantage is reduced or even offset. To reduce damage during high-speed sputtering of the cathode, a protective coating on the electron transport layer is useful. This protective layer, or buffer layer, must be strong enough to protect effectively. However, 'in addition to being resistant to the plasma, the buffer layer must not interfere with the operation of the device' and the performance of the device must be preserved.

Parthasarathy and his companions (Appl · Phys. Lett · 72, 2138 [1998]) _____ · 6-This paper size applies to China National Standard (CNS) A4 (210x297 public love ^ " 554640 A7 B7 V. Description of the invention () 4 'Propose a buffer layer application during the sputter deposition of a metal-free cathode, wherein the non-buffering layer is composed of copper phthalocyanine (Cupc) and zinc phthalocyanine (ZnPc). This buffer layer can prevent the sputtering process Damage to the underlying organic layer during this period.

Hung and his companions (j. Appl. Phys. 86, 4607 [1999]) revealed the use of CuPc buffers, which allow high-energy deposition of alloy cathodes. This cathode contains the low work function component Li, which is thought to diffuse through the buffer layer and provide an electron injection layer between the electron transport layer and the buffer layer. Patent application EP 〇 982 783 A2, Nakaya and his companions disclose a cathode of A1: Li alloy. The cathode is made by sputtering using a buffer layer, wherein the buffer layer is composed of a porphyrin or a tetracene compound and is deposited between the electron transport layer and the cathode. The device containing the sputtering electrode exhibits low driving voltage, high efficiency, and suppresses the growth of black spots. Although it is stated in all these references that effective devices can be made, no one has claimed to eliminate splash damage. In addition, a disadvantage of some of the prior art device structures is that they are not ideally suited for full-color devices that can emit different colors. Although CuPc is mostly transparent in the green wavelength region, the transparency is substantially lower in the red and blue wavelength regions. For use in full-color devices, the buffer layer should have completely uniform transparency throughout the visible wavelength range. Another undesirable feature is that organic buffer layers, such as phthalocyanine layers, may be thick and require longer deposition times. Therefore, the object of the present invention is to provide a cathode structure 'in an OLED device which has a fairly uniform response in the visible wavelength range and can provide electron injection. Another object of the present invention is to provide a cathode structure of an OLED device.

This paper size applies to China National Standard (CNS) A4 (21 × 297mm 554640 A7

It provides great protection against spoilage during the sputter deposition of the cathode layer. The above object can be achieved in a -0LED device, wherein the OLED device includes: a) a substrate b) an anode formed of a conductive material on the substrate; c) an electroluminescent material provided on the anode layer Luminescent layer; d) a buffer layer containing a heavy alkali metal compound provided on the luminescent layer; and e) a metal or metal alloy spray layer provided on the buffer layer, wherein the spray layer is selected to And this buffer layer is used to inject electrons. The advantage of the present invention is that damage to the organic layer during sputtering can be reduced, and the cathode can be manufactured at a high deposition rate. Another advantage of the present invention is that the buffer / spray layer cathode is ideal for full-color devices. Figure 1 outlines the layer structure of an OLED device; Figure 2 is a graph of the performance of a sputtering Mg cathode device as a function of the thickness of the RbF buffer layer; Figure 3 is a graph of the performance of a sputtering Mg cathode device as a function of the thickness of the CsF buffer layer Figures; Figure 4 is a graph of the performance of the sputtering Mg cathode device as a function of the thickness of the KF buffer layer; Figure 5 is a graph of the performance of the sputtering Mg cathode device as a function of the thickness of the LiF buffer layer; The performance of the device as a function of the thickness of the CsF buffer layer _ * 8-^ Paper size is suitable @@ 家 料 (CNS) A4 size (210 X 2 public love) Binding 554640 A7 B7 V. Description of the invention (<) Figure 6; and Figure 7 is a graph of the performance of the sputtering A1 cathode device as a function of the thickness of the RbF buffer layer. Throughout the explicit description, the initials are used to indicate the names of the different layers and the operating characteristics of the organic light emitting diode device. They are listed in Table 1 for reference. Table 1 OLED Organic Light Emitting Diode ITO Indium Tin Oxide HIL Hole Injection Layer HTL Hole Transport Layer EML Light Emitting Layer ETL Electron Transport Layer NPB 4, 双双 [N- (l- (Fluorenyl) -N-phenylamino] biphenyl (NPB) Alq gins- (8-Jin Ji-Pin) Ming LiF lithium fluoride CsF fluorinated insulation RbF It chemical such as KF potassium fluoride Mg magnesium A1 aluminum Turning now to FIG. 1, the OLED device 100 of the present invention includes a substrate 101, and the paper size of the paper is applicable to the Chinese National Standard (CNS) A4 specification (210X 297 mm) -9-554640 A7 B7 V. Description of the invention (7) Pole 102 Hole injection layer (HIL) 103, hole transport layer (HTL) 104, light emitting layer (EML) 105, electron transport layer (ETL) 106, buffer layer 107, and sputtering cathode 108. During operation, the anode and cathode are connected to the voltage source 109 via the conductor 110 and a current is passed through the organic layer, causing the OLED device to emit light or electroluminescence. Depending on the optical transparency of the anode and cathode, electroluminescence can be seen from either the anode side or the cathode side. The intensity of electroluminescence depends on the amount of current passing through the OLED device, so it depends on the light emission and electrical characteristics of the organic layer and the charge injection properties of the anode 102 and the sputtering cathode 108. The composition and function of the layers constituting the OLED device are described below. The substrate 101 may include glass, ceramic, or plastic. Because the manufacturing of OLED devices does not require high-temperature processes, any substrate that can withstand a process temperature of 100 ° C can be used, including most thermoplastics. The base plate can be in the form of a rigid plate, a flex plate, or a curved surface. The substrate 101 may include a support having an electronic backplane, and thus includes an active matrix substrate having electronic addressing and switching elements. Examples of the active matrix substrate include a single crystal chip wafer having a CMOS circuit element, a substrate having a South-temperature polysilicon thin film transistor, and a substrate having a low-temperature polysilicon thin film transistor. Those skilled in the art will understand that other circuit elements can be used to address and drive OLED devices. When a positive voltage relative to the cathode is applied to the OLED, the function of the anode 102 is to provide an injection hole into the organic layer. For example, in general transfers 1; 3-eight-4,720,432 it has been shown that indium tin oxide (ITO) can form an effective anode because of its relatively high work function. Because the ITO film itself is transparent, ITO-coated glass can provide an excellent support for the manufacture of OLED devices. Other suitable anode materials include high work function metals such as Au, Pt, Pd or this _-10-_ This paper size applies to China National Standard (CNS) A4 specifications (210X 297 mm) 554640 A7 B7 V. Description of the invention (some Metal alloy. The function of the hole injection layer (HIL) 103 is to increase the efficiency of hole injection into the organic layer from the anode 1. For example, porphorinic or phthalocyanine compounds have been shown in unlicensed un 4,885,21 1 Can be used as hole injection layer 103, resulting in improved luminous efficiency and operational stability. Other preferred HIL materials include CFx, which is a fluorinated polymer deposited by plasma enhanced vapor deposition, where X is less than or It is equal to 2 and greater than 0. The preparation method and characteristics of CFx have been disclosed in US-A-6,208,077, which is generally transferred. The function of the hole transport layer (HTL) 104 is to provide a hole to the light emitting layer (EML) 105 HTL materials include the various aromatic amines disclosed in us_A-4,720,432, which are generally transferred. Preferred HTL material types include tetraaryldiamines of formula (1). J

Ar1 At2 \ /

N-L-N / \

At Αχ3 (I) where

Ar, Ar1, Ar2KAr3 are independently selected from the group consisting of phenyl, biphenyl and fluorenyl; L is a divalent fluorenyl moiety or dn; d is a phenylene moiety; ___________- 11- National Standard of Finance (CNS) M specifications (21GX297 public love) ~-" 554640 A7 B7 V. Description of the invention (η is an integer from 1 to 4; and

At least one of Ar, Ar1, Ar2, and Ar3 is a fluorenyl moiety. The available aromatic tertiary amines (containing fused aromatic rings) are as follows: 4,4'-bis [N- (1 · fluorenyl) · N-phenylamino] biphenyl (npb) 4, 4 " -bis [1 ^ (1-fluorenyl) -small phenylamino] -p-terphenyl 4,4'-bis [> 1- (2-fluorenyl)-; ^ phenylamino ] Biphenyl 1,5-bis [1 ^ (1-fluorenyl)-: ^-phenylamino] fluorene 4,4'-bis [N- (2-fluorenyl) -N-phenylamino ] Biphenyl 4,4f-bis [N- (2-Dimethylphenyl) -N-phenylamino] biphenyl2.6-bis (di-p-tolylamino) fluorene2.6-bis [bis -(1-naphthyl) amino] naphthalene The function of the light emitting layer 105 in FIG. 1 is to provide light emission as a result of recombination of holes and electrons in this layer. Preferred embodiments of the light emitting layer include a host material doped with one or more fluorescent dyes. With this host-dopant composition, an extremely efficient OLED device can be built. At the same time, the color of EL devices can be adjusted with fluorescent dyes of different emission wavelengths in general host materials. US-A-4,769,292, which is generally assigned to Tang and his companions, describes this dopant combination of LED devices using Alq as the host material in great detail. As mentioned in US-A-4,769,292, which is generally assigned to Tang and his companions, the light emitting layer may include a green light emitting doping material, a blue light emitting doping material, or a red light emitting doping material. Car body materials include chelating metals such as 8- of Al, Mg, Li, and Zn. Charinol (8-q'uinoiioi) metal chelate compounds. Another type of preferred host material includes as usual transfer to 811 丨 and its companion 1; 1 _5,935,721

554640 A7 B7 5. Description of the invention (12 In the following examples, the appropriate structure and operating parameters corresponding to the listed initials should refer to Table 1. The basic organic EL medium is deposited on a 75 亳 micron NPB hole transport layer (HTL). It consists of 60nm Alq light emitting and electron transport (EML / ETL) layer. In a true 2 coater, the NpB and Alq layers are coated with a single pump pumping operation. Then the sample is transferred to a multifunctional coater And the remaining layers are deposited there in the proper order to produce various device configurations. The multifunctional applicator is equipped with an evaporation ship tungsten and a pin and a money spray gun. The metal test compound is evaporated from the resistance heating ship tungsten 'and A1 of the control device (also known as the standard product or standard cathode battery) is heated by electron beams in a radon vacuum to evaporate from the hanging steel. For spraying, pure air flowing at 30 SCCM will be backfilled to the deposition chamber to maintain a fixed pressure. Generally 16 mT (mtorr). Sputter deposition is accomplished by applying DC power to a pure Mg * A1 target. The deposition rate of Mg is ι · 2 nm / s at 80 watts, and the deposition rate of A1 is at 00 Below watts is υ nm / s. Admits deposition rate It can be easily controlled by choosing spray parameters. Although a single target is used for spraying money, but multiple targets can be sprayed at the same time to increase process throughput. RF can be used instead of DC as an alternative power source. It is considered that one has The alloy layer with better properties can be used to replace the metal layer. It is also known that the co-spattering of several targets can be used to replace the spraying of a single alloy target to adjust the composition of the alloy layer. The luminosity of the device can be measured using a PR650 radiometer. Depends on the current. The driving voltage V (volts) and luminosity B ((: (1 / m 2)) listed in the table and graph are measured when a current equivalent to 20 mA / m 2 passes through the device. Get 0 -15- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Equipment 554640 A7 B7 V. Description of the invention (13) Example 1 In Table 2, the device structures and performances of several devices of the invention are compiled, including the structure and performance of the control device. The devices 20 to 24, 1 to 10, HIL, HTL, and EML / ETL layers are the same, and the organic layer is deposited during a single pumping operation. The control device 20 with a standard cathode exhibits a luminosity of 565 cd / m 2 and an operating voltage of 5.9 volts. The standard cathode is a 60 nm thick A1 layer on a 0.5 nm LiF layer. consist of. It is assumed that the device did not suffer any damage during cathode deposition. The device 21 does not have a buffer layer; a 60 nm-thick Mg layer is directly sprayed on the Alq ETL layer. This device exhibits severely degraded performance as evidenced by its unusually high operating voltage and low efficiency relative to the control device 20. Due to the damage caused during the "§ splattering, the reduction is very possible, as it is known that thermal evaporation of Mg can produce an effective electron injection contact on the A1q ETL layer. Compared to the control device 20, the device 21 is in operation The increase in voltage and the loss in luminous efficiency are 5.2 volts and 77%, respectively. Device 22 has a 1 nm thick RbF layer, and a 60 nm thick Mg layer is sprayed under the same conditions as device 21 Splattered on it. Device 22 showed a luminosity of 538 cd / m 2 and an operating voltage of 6.5 volts, indicating a significantly better performance than device 21 1. This improvement is thought to be due to the RbF coating deposited on the Mg coating The protection provided during the layer. However, the performance of the device 22 is lower than that of the control device 20. In the structure of the device 23, a 2 nm thick RbF buffer layer is incorporated. The thicker buffer layer of the device 23 provides better Good protection against blowout damage and exhibits better operating voltage and luminosity than device 22. The operating voltage and luminous efficiency of device 23 are actually equal to these properties of standard devices. Increasing the thickness of RbF to 3 nm cannot be further improved Device

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554640 A7 B7 5. The performance of the invention (14). In devices 20, 23, and 24, small differences in performance are most likely due to changes in device structure and measurement inaccuracies. Therefore, a RbF buffer layer of about 2 nm thick can eliminate or reduce damage during spray deposition of the Mg coating layer. The performance of the sputtering device and the control device which varies with the thickness of the RbF buffer layer is also shown in FIG. 2. It has been observed that for Mg sputtering, the optimal RbF buffer layer thickness is greater than 1 nm and may be less than 3 nm. Table 2 Structure, layer thickness and performance of OLED devices with sputtered Mg cathodes and OLED devices with LiF / Al standard cathodes on various RbF buffer layers Device type Anode ITO thickness (nm) HIL CFx thickness (nm) HTL NPB Thickness (nm) EMUETL Alq Thickness (nm) LiF Thickness (nm) Buffer RbF Thickness (nm) Cathode AI Thickness (nm) Evaporated Cathode Mg Thickness (nm) Driving Voltage (Volts) ) Luminance (cd / m 2) 20 Control 42 1.0 75 60 0.5 60 5.9 565 21 Spray Mg Danger 42 1.0 75 60 0.0 60 11.1 129 22 Splash! ^; Cathode 42 1.0 75 60 1.0 60 6.5 538 23 Spray Splash Mg Danger 42 1.0 75 60 2.0 60 6.1 581 24 Cathode 42 1.0 75 60 3.0 60 6.3 607 Example 2

In Table 3, the device structure and performance of several kinds of the device of the present invention are compiled, including the structure and performance of the control device. The ITO, HIL, HTL ·, and EMUETL · layers of the devices 30 to 34 are the same. Controlled with a standard cathode | J Device 30 exhibits a luminosity of 603 cd / m 2 and an operating voltage of 5.7 volts. The standard cathode consists of a 60 nm thick A1 layer on 0.5 nm LiF -17- Paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) 554640 A7 B7 V. Description of invention (composed of layers. Assume that the device has no damage during cathode deposition. Device 31 does not have a buffer layer; 60 millimeters The micron-thick Mg layer is directly sprayed on the Aiq ETL layer. As evidenced by the unusually high operating voltage and low efficiency of the device relative to the control device 30, this device data suggests that the spraying can cause serious damage to the EL medium. The increase in the operating voltage and the loss in luminous efficiency of the device 31 are 5.4 volts and 79%, respectively. The device 32 has a 0.5 nm thick CsF layer. Under these same conditions as the device 31, the thickness of the 60 nm The Mg layer was spattered on it. Device 32 showed a luminosity of 479 cd / m 2 and an operating voltage of 7.2 volts, indicating a significantly better performance than device 3. This improvement is believed to be due to the CsF layer being spattered During Mg coating deposition The protection provided. However, the performance of the device 32 is lower than the control device 30. In the structure of the device 33, a 1.5 nm thick CsF buffer layer is incorporated. The thicker buffer layer of the device 33 provides better protection In order to prevent splash damage and exhibit better operating voltage and luminosity than device 32. However, the operating voltage and luminosity of device 33 are not equal to the properties of these standard devices 30, indicating that splash damage still exists

0 Increasing the CsF thickness to 3 nm can further improve device performance. The performance of the device 34 appears to be the same as that of the control device 30. This data suggests that the splatter damage in the device 34 has actually been eliminated. The small difference in performance between the devices 30 and 34 is most likely due to changes in the device structure and measurement inaccuracy. Therefore, a CsF buffer layer of about 3 nanometers thick can eliminate or reduce the shellfish damage during the sputter-deposited Mgs coating. The performance of the sputtering device and the control device as a function of the thickness of the CsF buffer layer is also shown in Figure 3. It is observed that for Mg sputtering, the optimal CsF buffer layer thickness is greater than 1.5 nm and possibly about 3 nm.

554640 A7 B7 V. Description of the invention (Table 3 Structure, layer thickness and performance of OLED devices with Mg cathode and LiF / A1 standard cathodes on various CsF buffer layers Device type Device type ITO thickness (nm) HIL CFx thickness (nm) HTL NPB thickness (nm) EML / ETL Alq thickness (nm) LiF thickness (nm) Buffered CsF thickness (nm) Evaporated cathode A1 thickness (nm) Sprayed cathode Mg Thickness (nm) Driving voltage (volts) Luminance (cd / m2) 30 Control 42 1.0 75 60 0.5 60 5.7 603 31 Spray Mg cathode 42 1.0 75 60 0.0 60 11.1 129 32 Spray Mg cathode 42 1.0 75 60 0.5 60 7.2 479 33 Mg cathode 42 1.0 75 60 1.5 60 6.3 549 34 Mg cathode 42 1.0 75 60 3.0 60 6.0 610

Installation Example 3 In Table 4, the device structures and performances of several devices of the present invention are compiled, including the structure and performance of the control device. The ITO, HIL, HTL, and EML / ETL layers of the devices 40 to 44 are the same, and the organic layer is deposited during a single pumping operation. The ITO coating of this example is different from those used in the devices of Examples 1 and 2. The control device 40 with a standard cathode exhibits a luminance of 811 cd / m 2 and an operating voltage of 7.1 volts. The standard cathode is composed of a 60 nm thick A1 layer on a 0.5 nm LiF layer. It is assumed that the device did not suffer any damage during cathode deposition. The device 41 has a 0.5 nm thick KF layer, and a 60 nm thick Mg layer is sprayed thereon. The device 41 showed a luminosity of only 664 cd / m 2 and an operating voltage of 8.0 volts, indicating that the 0.5 nm KF buffer layer did not provide sufficient protection against splash damage to the EL medium. __- 19-_ This paper size is in accordance with Chinese National Standard (CNS) A4 (210X 297 mm) 554640 A7 B7 V. Description of the invention (i7) Compared to the control device 40, the increase in the operating voltage of the device 41 and the light emission The losses in efficiency are 0.9 volts and 18%. Increasing the thickness of the KF buffer layer to 1.0 nm can improve the luminous efficiency, except that the luminosity is flat. However, beyond 1.5 nm, the voltage shows a significant increase. In the best sputtering device of this example, the luminosity of the device 42 exceeds 96% of the control device, but its voltage is 0.8 volts higher than that of the control device 40. Therefore, a KF buffer layer of about 1 nanometer thickness can reduce damage during spray deposition of Mg coatings. The performance of the spraying device and the control device as a function of the thickness of the KF buffer layer is also shown in FIG. 4. It has been observed that for Mg sputtering, the optimal KF buffer layer thickness is about 1 to 1.5 nm. Table 4 Structure, layer thickness and performance of OLED devices with sputtered Mg cathodes and LiF / A1 standard cathodes on various KF buffer layers Device type anode thickness ITO thickness (nm) HIL CFx thickness (nm) HTL NPB Thickness (Nm) EML / ETL Alq Thickness (Nm) LiF Thickness (Nm) Buffer KF Thickness (Nm) Thickness of evaporated electrode A1 (Nm) Thickness of sprayed electrode Mg (Nm) Driving voltage (volts) Luminance (cd / m2) 40 Control 85 1 75 60 0.5 60 7.1 811 41 Spray Mg 晗 柽 85 1 75 60 0.5 60 8.0 664 42 Splash \ ^ 喰 pole 85 1 75 60 1.0 60 7.9 780 43 Mg cathode spout 85 1 75 60 1.5 60 7.9 765 44 85 1 75 60 2.5 60 8.7 779 Example 4 Table 5 contains another set of devices with Mg cathodes sprayed on the LiF buffer layer and control devices with standard cathodes Device structure and performance. In addition, the paper size of the device is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ~ 20 ~ 554640 A7

From 1 to 55, the HIL, HTL, and EML / ETL layers are the same. For a standard battery with a standard cathode, the luminance displayed by the device 50 is 610 Cd / m 2 and its operating voltage is 6.6 volts. The standard cathode consists of a 60 nm thick A1 layer and 0.5 nm LiF. Made up of layers. The device 51 does not have a buffer layer, and is 60 nm thick. The layer is directly sprayed on the Alq etl layer. As evidenced by the unusually high operating voltage and low emission rate of device 51 relative to standard batteries, device 50, device 51's data suggest that the EL medium is severely sputtered, with the assumption that device 50 does not suffer any damage during cathode deposition. The device 52 has a 0.5 nm-thick LiF layer, and a 60 nm-thick Mg layer is sprayed thereon. The device 52 showed a luminosity of only 449 cd / m 2 and an operating voltage of 8.2 volts, indicating that a 0.5 nm LiF buffer layer could not provide sufficient protection against splash damage to the EL medium. Increasing the thickness of the LiF buffer layer to 10 nm can improve the luminous efficiency, but the exposure voltage becomes worse. Increasing the thickness of LiF further increased the operating voltage unilaterally, but the luminous efficiency was flat. The splatter with the thickest buffer layer, the luminosity of the device 55 is 87% of the control device 50, but its operating voltage is about 3 volts higher than the control device. The splash device with a buffer layer of 0.05 nm exhibits the lowest voltage in this series, but its voltage is 1.5 volts higher than the control device, and its luminosity is only Μ% of the control device. The performance of the spraying device and the control device is also shown in FIG. 5. From Tables 2 to 5 and Figures 2 to 5, it can be observed that the efficiency of using UF as a buffer layer for Mg sputtering is lower than that of CsF, RbF, or KF. 554640 A7 B7 V. Description of the invention (Table 5) Structure, thickness and performance of OLED devices with LiF / A1 standard cathodes and various LiF buffer layers with Mg cathodes splashed. Device numbering device type anode ITO thickness (nm) HIL CFx thickness (nm) HTL NPB thickness (nm) EML / ETL Alq thickness (nm) LiF thickness (nm) Buffer CsF thickness (nm) Evaporated cathode A1 thickness (nm) Sprayed Dangerous Mg thickness (nm) Driving voltage (volts) Luminance (cd / m2) 50 Control 42 1.0 75 60 0.5 60 6.6 610 51 Spray Mg cathode 42 1.0 75 60 0.0 60 11.1 129 52 Spray Mg cathode 42 1.0 75 60 0.5 60 8.2 449 53 Mg cathode 42 1.0 75 60 1.0 60 8.5 499 54 Mg cathode 42 1.0 75 60 2.0 60 9.0 531 55 Mg cathode 42 1.0 75 60 3.0 60 9.5 532 Example 5 is shown in the table In 6, the device structure and performance of several devices of the present invention are compiled, including the structure and performance of the control device. The ITO, HIL, nTL ·, and EML / ETL · layers of devices 60 to 65 are the same. Control with standard cathode Device 00 The displayed luminosity is 526 cd / m 2 and its operating voltage is 6.2 volts. The standard cathode consists of a 60 nm thick A1 layer on a 0.5 nm LiF layer. It is assumed that this device is during cathode deposition No damage. The device 61 does not have a buffer layer; the 60 nm thick A1 layer is sprayed directly on the Alq ETL layer. This device is severe as demonstrated by its unusually high operating voltage and low efficiency compared to the control device 60 Degraded performance. Due to the high work function of A1, and possible contribution from splash damage, this reduction is very possible. Device 61 1 increase in operating voltage and luminescence _-22-_ This paper size applies China National Standard (CNS) A4 (210X 297mm) 554640

The losses in efficiency are 51 volts and 39%, respectively. The device 62 has a layer of i nm thickness < CsF, and a 60 nm layer of A1 was sputtered thereon under the same conditions as the device 61. The device 62 showed a luminous intensity of 398 cd / m 2 and an operating voltage of 7.0 volts, indicating that it was significantly better than the energy generation of the device 61. This improvement is thought to be due to the protection provided by the CsF layer during the sputter deposition of the Al coating. However, the performance of the device 62 is lower than that of the control device 60. In the device 0 structure, a 2 nm thick CsF buffer layer is incorporated. The thicker buffer layer of device 63 provides better protection against splash damage and exhibits better operating voltage and luminosity than device 62. However, the operating voltage and luminosity of the device 63 are not equal to the properties of these standard devices 60, indicating that splash damage is still present. Increasing the thickness of CsF to 3 nm (device 64) does not further improve device performance. The performance of the device 64 and the control 60 is equal. This data suggests that the spray damage in device 64 has been substantially eliminated. The small difference between the device 60 and the medium performance is most likely due to changes in the device structure and measurement inaccuracy. Increasing the thickness of CsF to 4 nm cannot further increase the luminous efficiency and slightly increase the operating voltage. Therefore, a CsF buffer layer of about 3 nanometers thick can eliminate or reduce damage during spray deposition of the Al coating layer. The performance of the sputtering device and the control device as a function of the thickness of the CsF buffer layer is also shown in FIG. 6. It is observed that for A1 splash, the optimal CsF buffer layer thickness is greater than 3 nm and may be less than 4 nm. ______- 23 2. This paper size applies to China National Standard (CNS) Α4 size (210 × 297 mm)

Binding

554640 A7 B7 V. Description of the invention (21 Table 6 Structures of OLED devices with splashed A1 cathodes and LiF / A1 standard cathodes on various CsF buffer layers, thickness and performance Device numbering device type anode ITO thickness (nm) HIL CFx thickness (nm) HTL NPB thickness (nm) EML / ETL Alq thickness (nm) LiF thickness (nm) CsF thickness (nm) Evaporated cathode A1 thickness (nm) Cathodic cathode AI thickness (nm) Driving voltage (volts) Luminance (cd / m2) 60 Control 42 1.0 75 60 0.5 60 6.2 526 61 Spray AI cathode 42 1.0 75 60 60 11.3 321 62 Spray A1 cathode 42 1.0 75 60 1.0 60 7.0 398 63 Splash AI cathode 42 1.0 75 60 2.0 60 6.5 466 64 Splash AJ cathode 42 1.0 75 60 3.0 60 6.2 530 65 Splash A 丨 cathode 42 1.0 75 60 4.0 60 6.8 523 Example 6 is shown in Table 7 Assemble the device structure and performance of several devices of the invention, including the structure and performance of the control device. The ITO, HIL, HTL and EML / ETL layers of devices 70 to 75 are the same, and the organic layer is in a single pump Angry Transfer deposition. Table 7 shows the performance of the device relative to the control device 70. The graph in Figure 7 shows the normalized luminosity and voltage reduction as a function of the thickness of the RbF layer. The normalized luminosity and voltage reduction The system definition is as follows: If L is the luminosity of the device, V is the driving voltage of the device, Le is the luminosity of the control device, V. is the driving voltage of the control device, and then the normalized luminosity is L / Le, and the voltage reduction is V-Ve. Obviously, for the control battery, the normalized luminosity is 1, and the voltage drop is 0. The control battery has a standard cathode, which is composed of a 60 nm thick A1 layer on a 0.5 nm LiF layer. Group-24-This paper size applies Chinese National Standard (CNS) A4 (210X 297 mm) 55464〇A7 B7 i. Description of the invention

Into. The dummy controls did not suffer any damage during the cathode deposition. Device? ! No buffer layer; eight layers of 60¾ micron thickness are directly sprayed on the etl layer. This device exhibits severely degraded performance, as evidenced by its unusually high voltage drop and low normalized luminosity. This low performance is possible due to the high work function of A1, = and possible contribution from splash damage. The amount of voltage reduction and normalized luminosity were 5 丨 volts and 0.54, respectively. The device 72 has a 0.5 nm thick RbF layer, and a ⑽nm thick A1 layer is sputtered thereon under the same conditions as the device 71. The device 72 showed that the voltage drop was 2.5 volts and the normalized luminosity was 0.71, indicating a significantly better performance than the device 71. This improvement is thought to be due to the protection provided by the RbF layer during the sputter deposition of the Al coating. However, the performance of the device 72 is lower than that of the control device 70. In the structure of the device 73, a 15 micron thick RbF buffer layer is incorporated. The thicker buffer layer of device 73 provides better protection against splash damage and exhibits better operating voltage and luminosity than device 72. However, the amount of voltage drop and the normalized luminosity value of the device 73 are not equal to the properties of these control devices 70, indicating that splash damage is still present. Increasing the thickness of RbF to 2.5 nm (device 74) can further improve device performance. The performance of the device 74 and the control device 70 is not very similar. This data suggests that splash damage in the device 74 is greatly reduced. Small differences in performance between devices 70 and 74 are most likely due to changes in device structure and measurement inaccuracies. Increasing the thickness of RbF to 3.5 μm can slightly increase the luminous efficiency but greatly increase the operating voltage. Therefore, an RbF buffer layer of about 2.5 亳 m can reduce the harm during the sputter deposition of the coating layer. It can be observed from Fig. 7 that for A1 sputtering, the optimal RbF buffer layer thickness is about 3 µm.

554640 A7 B7 V. Description of the invention (23 Table 7 Various junction RbF buffer layers with sputtering A1 cathode and OLED device with LiF / Al standard cathode 丨 junction phase r 'λ I thickness and performance device number device type anode ITO thickness ( Nm) HIL CFx thickness (nm) HTL NPB thickness (nm) EML / ETL AJq thickness (nm) LiF thickness (nm) CsF thickness (nm) Evaporated cathode A1 thickness (nm) Sprayed cathode A1 thickness (nm) Voltage drop (volts) Normalized luminosity 70 Control 42 1.0 75 60 0.5 60 0.0 100 71 Spray AI danger 42 1.0 75 60 60 5.1 0.54 72 Spray A1 cathode 42 1.0 75 60 0.5 60 2.5 0.71 73 Splash A1 cathode 42 1.0 75 60 1.5 60 1.0 0.86 74 Mouth splash A1 cathode 42 1.0 75 60 2.5 60 0.7 0.91 75 Splash AI cathode 42 1.0 75 60 3.5 60 1.9 1.02 The above example shows a deposition The ultra-thin layer on the Alq electron transport layer provides great protection for the EL medium during the sputter deposition of the A1 and Mg coatings, where the ultra-thin layer contains a metal fluoride> compound. According to the present invention, The metal halide buffer layer can very effectively protect the organic EL medium from damage during sputtering deposition of the cathode coating. Note that this nanometer-thick buffer layer can virtually eliminate splash damage. Properties of the sputtering cathode device In essence, it can be equal to the control device with evaporated LiF / Al cathode. Other features of the present invention are included below. The thickness of the buffer layer is less than 10 nm but greater than 0 nm. OLED device. OLED devices with a micron but greater than 0.5 nm. _-? B-_ This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Claims (1)

No. Patent Application as ’Chinese application %% of scope of interest replaces July this year) S Patent application scope 1. An OLED device comprising: a) a substrate; b) an anode formed of a conductive material on the substrate; c) a light-emitting layer provided with an electroluminescent material on the anode layer; ', d) the light emission A buffer layer including retest metal dents is provided on the layer; and e) a base layer of metal or metal alloy mouth provided on the buffer layer, wherein the sputtering layer is selected to be used with the buffer layer to inject electrons. 2. The 0LED device according to item 丨 of the patent application scope, wherein the heavy alkali metal functional compound includes CsF, RbF, KF or a combination thereof. 3. The OLED device according to item 2 of the patent application, wherein the thickness of the buffer layer is less than 10 nm, but greater than 0 nm. 4. The LED device according to item 2 of the patent application range, wherein the thickness of the buffer layer is less than 5 nm, but greater than 0.5 nm. 5. The LED device according to item 1 of the patent application scope, wherein the metal comprises aluminum or thorium or a combination thereof. 6. The LED device according to item 1 of the patent application scope, wherein the metal further comprises silicon, hafnium, titanium, chromium, manganese, zinc, yttrium, zirconium, and hafnium or a metal alloy thereof. 7. The LED device according to item 丨 of the patent application, wherein the light-emitting layer comprises Alq. 8 · The LED device according to item 丨 of the patent application, wherein the light-emitting layer comprises one or more light-emitting doping materials. The size of this paper is suitable;?! Medium _ Home Standard (CNS) A4 size (21Gχ 297 public dream) Binding 554640 A BCD application patent scope 9 · An OLED device, including: a) a substrate; b) an anode formed of a conductive material on the substrate; c) a hole injection layer provided on the anode layer; d) the Hole transport layer provided on the hole injection layer; e) a light emitting layer provided with an electroluminescent material on the hole transport layer; 0 an electron transport layer provided on the light emitting layer; g) the electron transport layer A buffer layer comprising heavy alkali metal dents provided above; and h) a metal or metal alloy spray layer provided on the buffer layer, wherein the spray layer is selected to be used with the buffer layer for injecting electrons 9. 10 · —A method for manufacturing an OLED device, comprising the following steps: a) providing a substrate; b) forming an anode of a conductive material on the substrate; C) depositing an electroluminescent material on the anode layer It emits light / g, d) forming a layer containing a heavy alkali metal sulfonium on the light emitting layer; and a halide I buffer e) spraying a metal or metal alloy layer on the buffer layer. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)